The invention relates to mobile systems and particularly to implementing the acquisition of data relating to network-specific supplementary services in a telecommunications system, which comprises at least two mobile systems comprising user terminals and mobile networks, which in turn comprise mobile switching centres and subscriber databases, in which system at least one mobile network comprises at least one network-specific supplementary service and in which system at least one user terminal functions at least in two different mobile networks and supports at least one network-specific supplementary service.
Along with the development of mobile services, subscribers have been provided, in addition to conventional speech transmission, with a host of advanced teleservices. In addition to basic services provided free of charge, subscribers are offered several operator-specific and network-specific supplementary services.
The systems currently available include some by common agreements defined supplementary services; in some systems (such as in the GSM) the implementation of these services in the networks and in user terminals is highly standardized. Ever tighter competition has increased the need for different services and the tendency is towards an Intelligent Network (IN). The intelligent network is substantially an architecture which can be applied to telecommunications networks implemented with different network technologies. The intelligent network offers several modular functions, which can be interconnected in the planning and implementation of new services. The services are separate from the lowest level physical network structure, which allows each service to be offered in a substantially similar way, irrespective of in which network the operation takes place. Operators thus have more possibilities to diversify their range of services.
New services, however, set new demands also to the transmission of data and to its storage in the system. For this purpose e.g. in the GSM an Unstructured Supplementary Service Data (USSD) mechanism has been defined, which allows a subscriber and a service application to communicate with each other by character strings, in a way which is transparent to a user terminal and to the intermediate network elements .
Also the range of network technologies available has increased significantly. Several networks based on different technologies are already in commercial use, each one of which has its own advantages and restrictions. Digital European Cordless Telephone (DECT) is a telecommunications system developed within the ETSI for digital cordless communications and it usually operates within a frequency range of 1900 MHz. The DECT offers a good indoor coverage, high capacity and inexpensive call rates and user terminals. Equipment mobility in the DECT is, however, restricted and cell size varies between 25-100 metres, so a network of a working range covering e.g. a whole country is not practical to build with this technology.
Global System for Mobile Communications (GSM) is a widely spread pan-European mobile communications system standardized in the ETSI and it usually operates within a frequency range of 900 MHz. The GSM offers a reasonable indoor coverage and its cell size which can, when necessary, even exceed 30 km provides an extensive working range with reasonable cost. In addition, the large number of GSM operators ensures good opportunities for location monitoring all over the world. In densely populated areas capacity and optimization of the frequency spectrum are, however, becoming problematic in the GSM.
In a satellite mobile system, radio coverage is provided by means of satellites revolving around the earth, the satellites transmitting radio signals between User Terminals (UT) and Satellite Earth Stations (SES) in the same way as base stations. A beam provided by one satellite defines a coverage area, or cell, of a mobile system on the earth. The cells defined by satellites are arranged to form a continuous coverage area, whereby a mobile station is always within a coverage area. Since a satellite mobile network has a large cell size, the whole globe can, in principle, be covered by about ten satellites, depending on their orbit. Due to its configuration, a satellite system only covers outdoor areas; in other words, if a subscriber e.g. moves inside, the network connection weakens significantly or disappears.
The above shows that none of the technologies presented alone will solve all needs of the subscribers. A solution is offered by dual mode user terminals, which are capable of functioning in two networks implemented by different technology. Dual mode user terminals used in combinations GSM/DECT and GSM/DCS have already been presented, GSM/satellite user terminals are coming and as development advances, triple mode and even multimode user terminals are expected into the market. A typical feature in systems connected using dual, triple or multimode user terminals is that their network and switching sub-system (NSS) and the interface A between the network and switching sub-system and the radio system is based on existing PLMN network structures and the radio system is built according to the technology chosen.
The aim is that a subscriber moving from one network to another will have available all the supplementary network services that the subscriber""s user terminal supports. Supplementary services are always associated with a certain amount of data which has to be stored in permanent subscriber databases and transferred to a system visited at a particular time. Conventionally arrangements made regarding subscriber data relating to supplementary services cause changes in the system""s subscriber databases and protocols used for transferring said subscriber data. In connection with highly standardized systems already in use (such as the GSM), such changes are extremely difficult to implement and possibly even harmful to the compatibility achieved. As the number of network operators and the range of services increase, it is not reasonable to change the existing specifications to cater for new systems to be introduced in the future. This causes a significant problem as regards the introduction of new supplementary services.
An object of the present invention is to provide a solution allowing network-specific supplementary services to be offered, without the need to change existing systems, to a subscriber who via a user terminal uses the facilities of at least two networks implemented by different mobile systems.
This object is achieved with an arrangement of the invention characterized in that subscriber data relating to network-specific supplementary services of visited networks is permanently stored in a subscriber identity module of a user terminal and that the user terminal is arranged, at least when registering in a visited network, to automatically transmit the subscriber data relating to the supplementary services of the visited network for temporary storage to the subscriber database of the visited network.
The invention also relates to a method for implementing the acquisition of data relating to network-specific supplementary services in a telecommunications system, which comprises at least two mobile systems, which in turn comprise user terminals and mobile networks comprising mobile switching centres and subscriber databases, at least one user terminal functioning not only in a home network but also in at least one visited network, said terminal supporting at least one network-specific supplementary service in said visited network, the method comprising the steps of
initiating by said at least one user terminal the registration in the visited network, which comprises at least one network-specific supplementary service;
transferring the data relating to the common services of the home network and the visited network, in connection with the registration, from the subscriber database of the home network for temporary storage to the subscriber database of the visited network. The invention is characterized in that the method further comprises
permanently storing the subscriber data relating to the network-specific supplementary services of the visited network in the identity module of the user terminal,
transmitting, at least in connection with the registration in the visited network, the subscriber data relating to the network-specific supplementary services from the identity module of the user terminal for temporary storage to the subscriber database of the visited network.
The invention further relates to a user terminal of a mobile system according to claim 9, said terminal functioning in at least two mobile networks implemented by different network technologies and supporting at least one network-specific supplementary service. The user terminal is characterized in that subscriber data relating to network-specific supplementary services is permanently stored in an identity module of the user terminal, and that the user terminal is arranged, at least when registering in a visited network, to automatically transmit the subscriber data relating to the supplementary services of the visited network for temporary storage to the subscriber database of the visited network.
The invention also relates to a method according to claim 16 for updating subscriber data relating to network-specific supplementary services in a telecommunications system, which comprises at least two mobile systems, which in turn comprise user terminals and mobile networks comprising mobile switching centres and subscriber databases, at least one user terminal functioning not only in a home network but also in at least one visited network, said terminal supporting at least one network-specific supplementary service in said visited network. The method is characterized by
permanently storing subscriber data relating to the network-specific supplementary services of the visited network in an identity module of the user terminal,
receiving a request of change concerning the subscriber data relating to a network-specific service,
inquiring of a subscriber database of a home network for a routing address to a subscriber database of a subscriber""s location area for routing the subscriber data relating to the network-specific supplementary services from a network providing the service to the subscriber database,
establishing a radio connection between the user terminal and the network providing the service,
performing the data transmission associated with the network-specific supplementary services between the user terminal and the network providing the service, for changing the subscriber data in the identity module,
releasing the radio connection.
Home network here refers to that mobile network where the subscriber""s user terminal is registered. Visited network correspondingly here refers to a mobile network which is not the subscriber""s home network, but where the subscriber""s user terminal can function.
The invention is based on the idea that subscriber data related to network-specific supplementary services is stored in those parts of the mobile system that are managed by the subscriber and the operator providing the supplementary services. In the solution according to the invention, subscriber data relating to network-specific supplementary services is permanently stored in the subscriber identity module of the subscriber terminal, from where it is transferred for temporary storage to the subscriber database of a visited network. Other subscriber data are read as usually from the subscriber database of the subscriber""s home network. This allows limiting the changes concerning network-specific services to the network offering the service concerned. For instance, data relating to supplementary services of other networks are not needed in the subscriber database of the home network. Subscriber data related to network-specific services are transferred between the home network and a visited network using the protocols of the home network already available. The solution also includes the possibility of using a radio interface to change subscriber data relating to network-specific supplementary services from the network providing a particular service.
The present invention offers an inexpensive, easily implemented and well-functioning solution for arranging the acquisition of subscriber data between two different mobile systems in such a way that the subscriber will have available all network-specific supplementary services supported by the subscriber""s user terminal. Since subscriber databases or protocols of systems not offering a particular service need not be changed, the solution enables voiding the long and laborious process of changing network-specific supplementary services to make them available to all subscribers visiting a network.